87 



rostrum is often a little upturned and sometimes the whole rostrum is slis^htly ascendant; like 

 in the males from the Stations 122 and 173 some teeth on the rostrum proper are often longer, 

 i. e. more distant from one another, than the rest. 



We may conclude from the preceding observations that the number of teeth on the 

 upper margin of the rostrum varies rather much, from 9 to 14, and Alcock's suggestion that 

 a variety with 7 — 9, usually 9, teeth should be distinguished from a more typical form with 

 13 — 15 teeth, appears therefore not justified: in the species, examined by that author, usually 

 15 teeth were placed on the upper border, in the "Siboga" specimens 11, as has been indicated 

 above. Post-rostral carina distinct, reaching to near the after limit of the gastric region. A 

 microscopical tubercle, 0,3 mm. broad, exists in the middonsal line of the cardiac region, about 

 at the posterior fourth. Like in Nciiiaf. ensifer (S. I. Smith) var. producta Bate and in Nemal. 

 tenuirostris Bate var. Sibogae the shallow depression between the gastric and cardiac region 

 does not continue into the oblique lateral part of the cervical groove, which for the rest agrees 

 with that of these two species. Branchio-cardiac groove well defined, curved, not reaching the 

 posterior margin of the carapace nor uniting anteriorly with the cervical groove. Orbital 

 groove distinct. 



Abdomen a little more than twice as long as the carapace, rostrum included. Third 

 abdominal tergum moderately prominent posteriorly. Sixth somite in adult individuals twice as 

 long as broad. Telson constantly a little longer than 6"^ somite, flattened and slightly grooved 

 dorsally, with 8 or 9 pairs of dorsolateral spinules; the tip is armed with 3 pairs of spinules, 

 one pair at the extremity, at each side of which the spinules of the longest pair are implanted, 

 while those of the 3"' pair, the shortest of all, are implanted above those of the 2"''. While 

 in some specimens the telson extends by the terminal spinules beyond the outer uropods, in 

 other ones, as in the female N" i of the Table, it is much shorter and does even not reach 

 the tip of the endopodite. 



Like in the specimens of Nemat. cursor A. M.-Edw. from off the east coast of the 

 United States, the length of the eye and stalk does equal or exceed the breadth of the antenna] 

 scale; the eye extends almost to the far end of basal antennular article. In most specimens 

 the terminal spine of the scaphocerite reaches just beyond the tip of the blade. The antennular 

 peduncle, which is slightly longer than the rostrum, extends almost to the middle of the scapho- 

 cerite; 3«i article a little longer than 2"^, stylocerite slightly shorter than basal article. Upper 

 flagellum 2Y3-times as long as the animal from tip of rostrum to tip of telson, lower flagelluni 

 a little more than 3-times that length; the former somewhat thickened at base to a little beyond 

 the tip of the antcnnal scale, this thickened portion a little longer than the peduncle. Antennal 

 flagellum just as long as the lower flagellum of the upper antennae. 



The external maxillipeds reach in the adult female, long 104 mm., si.x-sevenths of the way 

 along the antennal scale; the penultimate joint reaches as far forward as the antennular peduncle, 

 terminal joint shorter than the penultimate with the spine at the distal extremity very small. 



The peraeopods of the 1^' pair extend by the chela and one-third or sometimes 

 even less than one-third of the carpus beyond the antennal scale; as regards their 

 measurements the\- agree with Nemat. cursor A. M.-Edw. from the east coast of the United 



